One other tactic when a shaak is zeroing in on a hooked bone is simply bust the tippet. If you're fishing 12lb or less, its not that difficult. In fact, lots of us do it without even trying on occaision
Just don't try to do it with the rod - it will probably break.
Dont worry too much about the fish swimming off with the fly. We all fishen' baahbless, don' we mon?